In January 2020 the municipal enterprise Pragrande d.o.o., seated in Pula, awarded the contract to the bidding consortium igr d.o.o and igr AG (today igr GmbH) to develop the above mentioned study.

The island group Brijuni - a total of 14 individual islands – is located in the northern of the Croatian Adriatic. In 1983 the area was declared as a national park.

5 of the 14 islands are being settled, but not permanently inhabited. The islands Veliki Brijun, Mali Brijun, Vanga, Galija and Sv. Jerolim were the subject of the study. On three islands there are numerous state-owned properties reserved exclusively for the government and the military. The summer residence of the former Yugoslav President Tito is on the island of Vanga.

The aim of the study was to present the possibilities of wastewater discharge and purification. The marginal criteria had to be taken into account, such as the national park, classification as the protected area Natura 2000, archaeological monuments, as well as touristic, governmental and military use of the area. The strongly fluctuating wastewater flow, in the winter months near 0 m³ per day, and in summer months up to 180 m³ per day, is a challenge for the dimensioning of the wastewater system, pumps and treatment plants. The central and decentralized system were analyzed and evaluated through economic criteria.

As a result of the study, it can be stated that a mixture of central and decentralized systems, including the transport of the wastewater by ship, is the most economical solution.

Based on the results of the study, the necessary planning should be initiated.

Preparing the study, considering the many boundary conditions, was a very interesting task for igr.

Suzana Josipović und Werner Andres